The present invention generally relates to box-making or finishing machines and more particularly to novel and improved apparatus including a vacuum transfer machine for use in box-making machines. The present invention also relates to a novel method and apparatus for retrofitting a box-making machine with a new vacuum transfer machine and impression cylinder.
An object of the present invention is to provide a novel and improved vacuum transfer machine for use in a box-making machine. Included herein is such a vacuum transfer machine that is highly suited for retrofitting into existing box-making machines.
Another object of the present invention is to provide a novel and improved vacuum transfer machine that incorporates an impression cylinder for the print operation. Included herein is such a machine that incorporates a novel method and apparatus for setting and adjusting the nip of the impression cylinder.
Another object of the present invention is to provide a novel and improved method and apparatus for retrofitting box-making or finishing machines with a vacuum transfer mechanism. Included herein is such a method and apparatus that retrofits vacuum transfer apparatus together with a print impression cylinder as a unit insertable into the box making machine.
An existing box-making machine is retrofitted by first removing the pull rolls and impression cylinder and other structures, for example, the existing elevating adjustment mechanism, permanent mesh arrangement, associated power train gears, associated rolls and shafts, and associated cross-ties. However the heavy duty frames and drums, including the print cylinder are left intact in the box-making machine.
A vacuum transfer machine is then inserted in the box-making machine and mounted to the existing frame to replace the pull rolls or other transfer apparatus that was removed.
Included in the vacuum transfer machine is an impression cylinder for printing, and transport rolls or wheels preferably on opposite sides of the impression cylinder for conveying the corrugated board or blank through the impression and print cylinders and to the die cutter. The boards are held against the transport rolls and the impression cylinder by vacuum generated in a vacuum chamber such as a hood which also contains the transport rolls and the impression cylinder. The vacuum chamber contains a plurality of vacuum doors or dampers for controlling the vacuum area in accordance with the size of the boards or blanks to be processed.
For creating the vacuum in the vacuum chamber, high performance xe2x80x9cvolume blowersxe2x80x9d rather than conventional pressure blowers are used. The blowers are included on the vacuum transfer machine. Exhaust air from the vacuum chamber is dispersed through filters over a wide area so that the exhaust is clean and free of strong air currents.